FDA issues HyQ complete response

Baxter International Inc. (NYSE:BAX) and partner Halozyme Therapeutics Inc. (NASDAQ:HALO) said FDA issued a complete response letter for a BLA for subcutaneous HyQ to treat primary immunodeficiency disorder (PID). According to the partners, the agency asked for additional preclinical data to address concerns about non-neutralizing antibodies generated against Halozyme's recombinant human PH20 hyaluronidase ( rHuPH20), which is a component in HyQ along with IV Gammagard, an IgG antibodies plasma-based therapy. The companies said FDA is concerned about possible effects on reproduction, development and fertility. Halozyme said elevated anti-rHuPH20 antibody titers were detected in the registration trial, but have not been associated with any adverse events. The agency did not request additional clinical trials. The partners plan to submit an amendment to the BLA following discussions with FDA, but did not disclose a timeline.

Halozyme said the concerns caused FDA to place a clinical hold on a Phase II trial of a combination of rHuPH20 and subcutaneous Cinryze from partner ViroPharma Inc. (NASDAQ:VPHM) for hereditary angioedema (HAE). According to ViroPharma, FDA said the issues are not specific to Cinryze and the company could evaluate subcutaneous Cinryze without rHuPH20. ViroPharma is preparing a Phase II trial of subcutaneous Cinryze without rHuPH20. Cinryze is approved in the U.S. and EU as an IV formulation. ...